More evidence that anaerobic oxidation of methane is prevalent in soils: Is it time to upgrade our biogeochemical models?

0444689 - BC 2016 RIV GB eng J - Článek v odborném periodiku
Gauthier, M. - Bradley, R.L. - Šimek, Miloslav
More evidence that anaerobic oxidation of methane is prevalent in soils: Is it time to upgrade our biogeochemical models?
Soil Biology and Biochemistry. Roč. 80, January (2015), s. 167-174. ISSN 0038-0717
Grant CEP: GA ČR GA526/09/1570
Institucionální podpora: RVO:60077344
Klíčová slova: anaerobic oxidation of methane * isotope dilution * peatland soil * shoreline soil * acid sulfate soil * alternative electron acceptors
Kód oboru RIV: EH - Ekologie - společenstva
Impakt faktor: 4.152, rok: 2015

Estimating future fluxes of CH₄ between land and atmosphere requires well-conceived process-based biogeochemical models. Current models do not represent the anaerobic oxidation of methane (AOM) in land surface soils, in spite of increasing evidence that this process is widespread. Our objective was to determine whether AOM, or potential AOM, commonly occurs in 20 hydromorphic soils spanning a wide range of chemical properties. Bulk soil samples were collected under shallow water near the shoreline of 15 recently drained fish ponds in southern Bohemia (Czech Republic), as well as from below the water table at 3 peatland locations in northeast Scotland and 2 acid sulfate soils on the southern coast of Finland. Each soil slurry was incubated under both oxic and anoxic conditions, with or without the addition of alternative electron acceptors (SO₄^2- and NO₃^-) or H₂PO₄^-. Here, "oxic" and "anoxic" conditions refer to anoxic soil respectively incubated in a headspace containing air or argon. Using the isotope dilution method, we determined the gross production and oxidation rates of CH₄ after 2 days incubation under oxic headspace conditions, and after 2, 21 and 60 days incubation under anoxic conditions. Large differences in net CH₄ fluxes were observed between soil types and between incubation conditions. AOM was detected in each of the 20 bulk soil samples, which spanned >6 pH units and 2 orders of magnitude in organic C content. Significant positive relationships were found between AOM and gross CH₄ production rates under anoxic conditions, resulting in AOM rates that were sometimes higher than CH₄ oxidation rates under oxic headspace conditions. There was no relationship between net and gross CH₄ production rates, such that 2 soil types could display similar low net rates, yet conceal very large differences in gross rates.
Trvalý link: http://hdl.handle.net/11104/0249911